春季南海鸢乌贼栖息地时空分布及其年际差异分析

根据2014—2017年春季南海鸢乌贼(Sthenoteuthis oualaniensis)渔业数据以及海表面温度(Sea surface temperature,SST)、叶绿素a浓度(Chlorophyll-a,Chl-a)和海面高度(Sea surface height,SSH)3个关键环境因子,构建栖息地指数(Habitat suitable index,HSI)模型以厘清春季南海鸢乌贼栖息地的时空分布规律,并分析各年栖息地时空分布差异及其成因。结果发现,春季南海鸢乌贼渔场环境呈现SST和SSH北低南高、Chl-a沿岸高而远海低的分布特征;鸢乌贼适宜栖息地主要分布在110°E—119°E,栖息地的分布与3个环境因子的空间分布显著相关;2014—2017年HSI空间距平值呈逐年下降趋势,且在空间上具有显著年际差异,同时空间分布具有显著的经、纬度差异;适宜环境范围逐年缩小,导致鸢乌贼适宜栖息地面积呈现下降趋势。研究表明,春季南海鸢乌贼栖息地的时空分布与渔场环境因子显著相关,其年际差异可由各年环境因子的时空分布来解释。

Spatio-temporal variability of habitat distribution of Sthenoteuthis ouala-niensis in South China Sea and its interannual variation

Based on the fishery data of Sthenoteuthis oualaniensis and three critical environmental factors including sea surface temperature(SST),Chlorophyll-a(Chl-a)and sea surface height(SSH),we developed an integrated habitat suitability index(HSI)model to examine the spatio-temporal distribution of potential habitat of S.oualaniensis in the South China Sea in spring and clarify the law of the spatio-temporal distribution of habitat of the fish.Results show that the SST and SSH on the fishing ground of S.oualaniensis were lower in the northern waters but higher in the southern waters.The Chl-a concentration was higher in the coastal waters but lower in the pelagic waters.The suitable habitats of S.oualaniensis in spring mainly distributed in the regions between 110°E and 119°E,and its spatial location was consistent of the overlapping areas among the suitable environmental ranges of the above-mentioned three factors.Besides,the HSI anomaly from 2014 to 2017 decreased gradually and showed interannual variability in space.Annually suitable range of each environmental factor exhibited a decreasing trend,and the unfavorable range of each environmental factor showed an increasing trend,leading to the contracted suitable habitats and enlarged unfavorable habitats for S.oualaniensis.The longitudinal and latitudinal distribution of suitable habitats of S.oualaniensis also showed significant interannual variability from year to year.The results indicate that the habitats of S.oualaniensis are closely associated with the environmental factors on their fishing ground;the variability of spatial and temporal of potential habitat hotspots can be explained by the spatio-temporal distribution of environmental conditions.